Women have three holes down there, not two. To be fair to him, the only women in his life he lived with for any length of time was his mother who was extremely private about all bathroom stuff and hid all her monthly items.
Lol, it took me until I was 12 to figure that one out. I always thought women had cloacas, like birds. Turns out that a curious kid with an aging encyclopedia and parents that absolutely did not want to talk about biology are a bad combination.